* {
    margin: 0;
    padding: 0;
}

body,
html {
    height: 100%;
}

ul {
    list-style: none;
}

.header {
    height: 50px;
    background-color: #545c64;
    line-height: 50px;
    text-align: center;
    font-size: 24px;
    color: #fff;
}

.main {
    display: flex;
    position: absolute;
    top: 50px;
    bottom: 40px;
    width: 100%;
}

.left {
    flex: 0 0 20%;
    height: 100%;
    background-color: #545c64;
}

.left li {
    height: 45px;
    background-color: #a0a0a0;
    border-bottom: 1px solid #fff;
    line-height: 45px;
    text-align: center;
}

.left li a {
    display: inline-block;
    width: 100%;
    height: 100%;
    text-decoration: none;
    color: #fff;
}

.right {
    flex: 1;
    margin: 5px;
    text-align: center;
}

.main-content {
    margin-top: 10px;
    text-align: center;
}

.main-content h4 {
    margin: 20px 0;
}

.main-content table {
    width: 100%;
    border-collapse: collapse;
}

.main-content th {
    background-color: #ddd;
}

.main-content th,
td {
    height: 35px;
    border: 1px solid #eee;
    font-size: 12px;
}

.right button {
    margin: 20px 0;
    padding: 0 20px;
    border: 1px solid lightskyblue;
    background-color: #ecf5ff;
    line-height: 30px;
    font-size: 12px;
    cursor: pointer;
}

.footer {
    position: absolute;
    bottom: 0;
    width: 100%;
    height: 40px;
    background-color: #888;
    line-height: 40px;
    text-align: center;
    font-size: #888;
    color: #fff;
}